interop: Ingress Filtering for Interop Enabled Mempool

Co-authored-by: Tyler Smith <mail@tcry.pt>
Co-authored-by: Diederik Loerakker <proto@protolambda.com>

core/error.go

@@ -84,6 +84,10 @@ var (
 	// current network configuration.
 	ErrTxTypeNotSupported = types.ErrTxTypeNotSupported
 
+	// ErrTxFilteredOut indicates an ingress filter has rejected the transaction from
+	// being included in the pool.
+	ErrTxFilteredOut = errors.New("transaction filtered out")
+
 	// ErrTipAboveFeeCap is a sanity error to ensure no one is able to specify a
 	// transaction with a tip higher than the total fee cap.
 	ErrTipAboveFeeCap = errors.New("max priority fee per gas higher than max fee per gas")

core/txpool/ingress_filters.go

@@ -0,0 +1,57 @@
+package txpool
+
+import (
+	"context"
+	"time"
+
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/core/types/interoptypes"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+// IngressFilter is an interface that allows filtering of transactions before they are added to the transaction pool.
+// Implementations of this interface can be used to filter transactions based on various criteria.
+// FilterTx will return true if the transaction should be allowed, and false if it should be rejected.
+type IngressFilter interface {
+	FilterTx(ctx context.Context, tx *types.Transaction) bool
+}
+
+type interopFilter struct {
+	logsFn  func(tx *types.Transaction) ([]*types.Log, error)
+	checkFn func(ctx context.Context, ems []interoptypes.Message, safety interoptypes.SafetyLevel) error
+}
+
+func NewInteropFilter(
+	logsFn func(tx *types.Transaction) ([]*types.Log, error),
+	checkFn func(ctx context.Context, ems []interoptypes.Message, safety interoptypes.SafetyLevel) error) IngressFilter {
+	return &interopFilter{
+		logsFn:  logsFn,
+		checkFn: checkFn,
+	}
+}
+
+// FilterTx implements IngressFilter.FilterTx
+// it gets logs checks for message safety based on the function provided
+func (f *interopFilter) FilterTx(ctx context.Context, tx *types.Transaction) bool {
+	logs, err := f.logsFn(tx)
+	if err != nil {
+		log.Debug("Failed to retrieve logs of tx", "txHash", tx.Hash(), "err", err)
+		return false // default to deny if logs cannot be retrieved
+	}
+	if len(logs) == 0 {
+		return true // default to allow if there are no logs
+	}
+	ems, err := interoptypes.ExecutingMessagesFromLogs(logs)
+	if err != nil {
+		log.Debug("Failed to parse executing messages of tx", "txHash", tx.Hash(), "err", err)
+		return false // default to deny if logs cannot be parsed
+	}
+	if len(ems) == 0 {
+		return true // default to allow if there are no executing messages
+	}
+
+	ctx, cancel := context.WithTimeout(ctx, time.Second*2)
+	defer cancel()
+	// check with the supervisor if the transaction should be allowed given the executing messages
+	return f.checkFn(ctx, ems, interoptypes.Unsafe) == nil
+}

core/txpool/ingress_filters_test.go

@@ -0,0 +1,302 @@
+package txpool
+
+import (
+	"context"
+	"errors"
+	"net"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/core/types/interoptypes"
+	"github.com/ethereum/go-ethereum/params"
+	"github.com/stretchr/testify/require"
+)
+
+func TestInteropFilter(t *testing.T) {
+	t.Run("Tx has no logs", func(t *testing.T) {
+		logFn := func(tx *types.Transaction) ([]*types.Log, error) {
+			return []*types.Log{}, nil
+		}
+		checkFn := func(ctx context.Context, ems []interoptypes.Message, safety interoptypes.SafetyLevel) error {
+			// make this return error, but it won't be called because logs are empty
+			return errors.New("error")
+		}
+		// when there are no logs to process, the transaction should be allowed
+		filter := NewInteropFilter(logFn, checkFn)
+		require.True(t, filter.FilterTx(context.Background(), &types.Transaction{}))
+	})
+	t.Run("Tx errored when getting logs", func(t *testing.T) {
+		logFn := func(tx *types.Transaction) ([]*types.Log, error) {
+			return []*types.Log{}, errors.New("error")
+		}
+		checkFn := func(ctx context.Context, ems []interoptypes.Message, safety interoptypes.SafetyLevel) error {
+			// make this return error, but it won't be called because logs retrieval errored
+			return errors.New("error")
+		}
+		// when log retrieval errors, the transaction should be allowed
+		filter := NewInteropFilter(logFn, checkFn)
+		require.True(t, filter.FilterTx(context.Background(), &types.Transaction{}))
+	})
+	t.Run("Tx has no executing messages", func(t *testing.T) {
+		logFn := func(tx *types.Transaction) ([]*types.Log, error) {
+			l1 := &types.Log{
+				Topics: []common.Hash{common.BytesToHash([]byte("topic1"))},
+			}
+			return []*types.Log{l1}, errors.New("error")
+		}
+		checkFn := func(ctx context.Context, ems []interoptypes.Message, safety interoptypes.SafetyLevel) error {
+			// make this return error, but it won't be called because logs retrieval doesn't have executing messages
+			return errors.New("error")
+		}
+		// when no executing messages are included, the transaction should be allowed
+		filter := NewInteropFilter(logFn, checkFn)
+		require.True(t, filter.FilterTx(context.Background(), &types.Transaction{}))
+	})
+	t.Run("Tx has valid executing message", func(t *testing.T) {
+		// build a basic executing message
+		// the executing message must pass basic decode validation,
+		// but the validity check is done by the checkFn
+		l1 := &types.Log{
+			Address: params.InteropCrossL2InboxAddress,
+			Topics: []common.Hash{
+				common.BytesToHash(interoptypes.ExecutingMessageEventTopic[:]),
+				common.BytesToHash([]byte("payloadHash")),
+			},
+			Data: []byte{},
+		}
+		// using all 0s for data allows all takeZeros to pass
+		for i := 0; i < 32*5; i++ {
+			l1.Data = append(l1.Data, 0)
+		}
+		logFn := func(tx *types.Transaction) ([]*types.Log, error) {
+			return []*types.Log{l1}, nil
+		}
+		var spyEMs []interoptypes.Message
+		checkFn := func(ctx context.Context, ems []interoptypes.Message, safety interoptypes.SafetyLevel) error {
+			spyEMs = ems
+			return nil
+		}
+		// when there is one executing message, the transaction should be allowed
+		// if the checkFn returns nil
+		filter := NewInteropFilter(logFn, checkFn)
+		require.True(t, filter.FilterTx(context.Background(), &types.Transaction{}))
+		// confirm that one executing message was passed to the checkFn
+		require.Equal(t, 1, len(spyEMs))
+	})
+	t.Run("Tx has invalid executing message", func(t *testing.T) {
+		// build a basic executing message
+		// the executing message must pass basic decode validation,
+		// but the validity check is done by the checkFn
+		l1 := &types.Log{
+			Address: params.InteropCrossL2InboxAddress,
+			Topics: []common.Hash{
+				common.BytesToHash(interoptypes.ExecutingMessageEventTopic[:]),
+				common.BytesToHash([]byte("payloadHash")),
+			},
+			Data: []byte{},
+		}
+		// using all 0s for data allows all takeZeros to pass
+		for i := 0; i < 32*5; i++ {
+			l1.Data = append(l1.Data, 0)
+		}
+		logFn := func(tx *types.Transaction) ([]*types.Log, error) {
+			return []*types.Log{l1}, nil
+		}
+		var spyEMs []interoptypes.Message
+		checkFn := func(ctx context.Context, ems []interoptypes.Message, safety interoptypes.SafetyLevel) error {
+			spyEMs = ems
+			return errors.New("error")
+		}
+		// when there is one executing message, and the checkFn returns an error,
+		// (ie the supervisor rejects the transaction) the transaction should be denied
+		filter := NewInteropFilter(logFn, checkFn)
+		require.False(t, filter.FilterTx(context.Background(), &types.Transaction{}))
+		// confirm that one executing message was passed to the checkFn
+		require.Equal(t, 1, len(spyEMs))
+	})
+}
+
+func TestInteropFilterRPCFailures(t *testing.T) {
+	tests := []struct {
+		name        string
+		networkErr  bool
+		timeout     bool
+		invalidResp bool
+	}{
+		{
+			name:       "Network Error",
+			networkErr: true,
+		},
+		{
+			name:    "Timeout",
+			timeout: true,
+		},
+		{
+			name:        "Invalid Response",
+			invalidResp: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Create mock log function that always returns our test log
+			logFn := func(tx *types.Transaction) ([]*types.Log, error) {
+				log := &types.Log{
+					Address: params.InteropCrossL2InboxAddress,
+					Topics: []common.Hash{
+						common.BytesToHash(interoptypes.ExecutingMessageEventTopic[:]),
+						common.BytesToHash([]byte("payloadHash")),
+					},
+					Data: make([]byte, 32*5),
+				}
+				return []*types.Log{log}, nil
+			}
+
+			// Create mock check function that simulates RPC failures
+			checkFn := func(ctx context.Context, ems []interoptypes.Message, safety interoptypes.SafetyLevel) error {
+				if tt.networkErr {
+					return &net.OpError{Op: "dial", Err: errors.New("connection refused")}
+				}
+
+				if tt.timeout {
+					return context.DeadlineExceeded
+				}
+
+				if tt.invalidResp {
+					return errors.New("invalid response format")
+				}
+
+				return nil
+			}
+
+			// Create and test filter
+			filter := NewInteropFilter(logFn, checkFn)
+			result := filter.FilterTx(context.Background(), &types.Transaction{})
+			require.Equal(t, false, result, "FilterTx result mismatch")
+		})
+	}
+}
+
+func TestInteropMessageFormatEdgeCases(t *testing.T) {
+	tests := []struct {
+		name          string
+		log           *types.Log
+		expectedError string
+	}{
+		{
+			name: "Empty Topics",
+			log: &types.Log{
+				Address: params.InteropCrossL2InboxAddress,
+				Topics:  []common.Hash{},
+				Data:    make([]byte, 32*5),
+			},
+			expectedError: "unexpected number of event topics: 0",
+		},
+		{
+			name: "Wrong Event Topic",
+			log: &types.Log{
+				Address: params.InteropCrossL2InboxAddress,
+				Topics: []common.Hash{
+					common.BytesToHash([]byte("wrong topic")),
+					common.BytesToHash([]byte("payloadHash")),
+				},
+				Data: make([]byte, 32*5),
+			},
+			expectedError: "unexpected event topic",
+		},
+		{
+			name: "Missing PayloadHash Topic",
+			log: &types.Log{
+				Address: params.InteropCrossL2InboxAddress,
+				Topics: []common.Hash{
+					common.BytesToHash(interoptypes.ExecutingMessageEventTopic[:]),
+				},
+				Data: make([]byte, 32*5),
+			},
+			expectedError: "unexpected number of event topics: 1",
+		},
+		{
+			name: "Too Many Topics",
+			log: &types.Log{
+				Address: params.InteropCrossL2InboxAddress,
+				Topics: []common.Hash{
+					common.BytesToHash(interoptypes.ExecutingMessageEventTopic[:]),
+					common.BytesToHash([]byte("payloadHash")),
+					common.BytesToHash([]byte("extra")),
+				},
+				Data: make([]byte, 32*5),
+			},
+			expectedError: "unexpected number of event topics: 3",
+		},
+		{
+			name: "Data Too Short",
+			log: &types.Log{
+				Address: params.InteropCrossL2InboxAddress,
+				Topics: []common.Hash{
+					common.BytesToHash(interoptypes.ExecutingMessageEventTopic[:]),
+					common.BytesToHash([]byte("payloadHash")),
+				},
+				Data: make([]byte, 32*4), // One word too short
+			},
+			expectedError: "unexpected identifier data length: 128",
+		},
+		{
+			name: "Data Too Long",
+			log: &types.Log{
+				Address: params.InteropCrossL2InboxAddress,
+				Topics: []common.Hash{
+					common.BytesToHash(interoptypes.ExecutingMessageEventTopic[:]),
+					common.BytesToHash([]byte("payloadHash")),
+				},
+				Data: make([]byte, 32*6), // One word too long
+			},
+			expectedError: "unexpected identifier data length: 192",
+		},
+		{
+			name: "Invalid Address Padding",
+			log: &types.Log{
+				Address: params.InteropCrossL2InboxAddress,
+				Topics: []common.Hash{
+					common.BytesToHash(interoptypes.ExecutingMessageEventTopic[:]),
+					common.BytesToHash([]byte("payloadHash")),
+				},
+				Data: func() []byte {
+					data := make([]byte, 32*5)
+					data[0] = 1 // Add non-zero byte in address padding
+					return data
+				}(),
+			},
+			expectedError: "invalid address padding",
+		},
+		{
+			name: "Invalid Block Number Padding",
+			log: &types.Log{
+				Address: params.InteropCrossL2InboxAddress,
+				Topics: []common.Hash{
+					common.BytesToHash(interoptypes.ExecutingMessageEventTopic[:]),
+					common.BytesToHash([]byte("payloadHash")),
+				},
+				Data: func() []byte {
+					data := make([]byte, 32*5)
+					data[32+23] = 1 // Add non-zero byte in block number padding
+					return data
+				}(),
+			},
+			expectedError: "invalid block number padding",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var msg interoptypes.Message
+			err := msg.DecodeEvent(tt.log.Topics, tt.log.Data)
+			if tt.expectedError != "" {
+				require.Error(t, err)
+				require.ErrorContains(t, err, tt.expectedError)
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}